The present invention relates to scissors sharpeners of the type which use a disk type sharpening member. Conventional sharpeners of this type have a tendency for the disks to grab and often forceably cause the user to lose physical control of the scissors when the scissors is positioned parallel to the disk face. In addition, the user loses control of the edge sharpening angle which results in a gouging, scalloping or otherwise creating the formation of undesirable grooves in the scissors blades. One of the difficulties with prior scissors sharpeners is the inability to take into account the unbalanced weight of the scissors handle which requires the user to carefully control the amplitude of applied force between the scissors and the rotating disk. The applied force in such prior art disk sharpeners is thus a strong function of the operator's techniques and skills as well as the scissors thickness and geometry and other design factors. Without proper control gouging and scalloping frequently occurs.
The parent patents disclose various forms of magnetic guides for guiding the blade to be sharpened into contact with a double sided abrasive coated planar sharpening member. U.S. Pat. No. 4,627,194, for example, discloses an orbitally driven sharpening member, while U.S. Pat. No. 4,716,689 discloses a rotating sharpening member. The magnetic guides accurately control the sharpening angle and pressure and minimize the amount of sharpening debris remaining on the abrasive surface in use. The parent patents also disclose multiple sharpening sections wherein the guides dispose the blade at different angles with respect to the sharpening member so that the sharpening is done in multiple stages, each at progressively larger angles. The parent patens also suggest using diamond abrasive particles and using different abrasive grit sizes for different sharpening sections.
U.S. Pat. No. 4,627,194 discloses the magnetic guide surface having two opposite polarity magnetic poles comprising a north pole and a south pole oriented such that each pole lies along the line which is substantially parallel to the line at which the plane of the guide surface intersects the abrasive surface. One of the poles is disposed along a portion of the magnetic guide surface remote from the abrasive surface and the other of the poles is disposed along the portion of the guide surface contiguous to the abrasive surface to create the magnetic field at the abrasive surface. The magnetic field is of a strength to provide a thrust to move the cutting edge facet of the blade into contact with the abrasive surface and to provide a force to hold the cutting edge facet in contact with the abrasive surface while the abrasive surface is in motion.